A power supply device using a secondary battery has been used for a power supply for driving a vehicle, for example. The power supply device mentioned above is provided with a plurality of battery cells 91, a plurality of separators 92, a pair of bind bars 95, and a pair of end plates 94, as illustrated in an exploded perspective view in FIG. 8. Each of separators 92 is interposed between adjacent battery cells 91. Battery cells 91 and separators 92 are stacked in an alternating fashion to form battery stacked body 99. Both end faces of battery stacked body 99 in the stacking direction of battery cells 91 are respectively covered by end plates 94. Respective bind bars 95 extend along the stacking direction of battery cells 91, and are fixed to end plates 94 on both ends of battery stacked body 99. In the power supply device mentioned above, electrode terminals 93 of battery cells 91 are electrically connected each other through bus bars 97. The bus bar is configured of metal board having excellent conductivity.
Since members of the battery cells or the like constituting the power supply device include manufacturing allowance, distances between the electrode terminals adjacently disposed are not necessarily constant, and therefore it is necessary to absorb dispersion of these. Further, in a case where the power supply device receives outer force, it happens that the battery cells adjacently disposed are relatively misaligned. In this case, in order to absorb the misalignment through the bus bar, it is required that the bus bar has flexibility capable of being resiliently deformed.
As the way where the bus bar has flexibility, the bus bar in which bending processing is carried out, has been known (refer to Unexamined Japanese Patent Publication No. 2013-197017, for example). However, in the conventional configuration, the bent portion for buffering stress is disposed between two connection parts connected to the electrode terminals. In this shape, in a case where size between terminals of adjacent cells is short, there is a problem that forming the bus bar (press working) becomes difficult.